Gauging devices for determining dimensions at known locations on a workpiece are commonly used to verify compliance with manufacturing specifications. Such gauging devices may be contact devices such as mechanical micrometers and electronic LVDT devices. Non-contact gauging devices also exist in the prior art such as laser gauges.
Notwithstanding the various uses of prior art gauges, a need has heretofore existed for a system which can be used to accurately determine the profile of elongate workpieces machined on centerless grinder assemblies, as well as other elongate workpieces. One such system is disclosed in related U.S. Pat. No. 5,674,106, which is assigned to the common assignee of the present invention, Royal Master Grinders, Inc. of Oakland, N.J.
A prior art system which utilizes a gauge to take post-manufacturing measurements is disclosed in U.S. Pat. No. 4,756,126 which issued to Pozzetti. The gauging system disclosed in the -126 patent has various shortcomings. For example, it would require two or more gauge heads to determine the diameter at different sections of an elongate workpiece. In this regard, the workpiece machined by the grinder disclosed in the -126 patent is longitudinally fixed during grinding operations. The gauging device 12 disclosed therein is mounted on a slide 11 which moves the gauging device toward or away from the fixed workpiece perpendicularly to the longitudinal axis of the workpiece. There is no disclosure, teaching or suggestion whatsoever to use the gauging device disclosed in the -126 patent by continuously detecting dimensions of an elongate workpiece and effecting relative longitudinal movement between the workpiece and the gauging device.
The gauging system of the present invention is particularly efficient for determining the profile of elongate workpieces machined on centerless grinder assemblies. However, it may be also be used to determine the profile of workpieces machined or manufactured on various other apparatus.
A centerless grinder is a manufacturing machine tool which can be used to grind elongate cylindrical workpieces such as wires, rods, pins, golf club shafts and the like. Workpieces machined on centerless grinder may have a constant cross-sectional diameter or may have various tapered sections including slight tapered sections and abrupt diametrical changes. The process of using a centerless grinder to machine such workpieces is also known as grinding the workpieces or removing stock from the workpiece to obtain the desired configuration. Centerless grinders are particularly useful where precision tolerances are required and where particularly accurate profiles are desirable.
Centerless grinders include three main components. A work wheel, which is also known in the art as a grinding wheel, a regulating wheel and a work rest blade. The work wheel is the machine component that usually performs the actual removal of stock from the workpiece. The work wheel thus determines the surface finish and the overall configuration of the workpiece. The surface texture of the work wheel can be varied depending upon the particular grinding operation desired.
The regulating wheel is the machine component which directs and guides the workpiece to the work wheel. The regulating wheel is also responsible for driving the workpiece and causing rotation thereof during the grinding process.
The work rest blade is the machine component which provides support for the workpiece during machining (i.e., grinding) operations. The regulating wheel will cause the workpiece to rotate on the work rest blade while the work wheel remove an amount of stock required to obtain the desired diameter or taper of the associated workpiece. Prior art work rest blades include horizontal or angled support surfaces. The particular orientation of the work rest blade surface may be selected in accordance with the required configuration of the completed workpiece.
Royal Master Grinders, Inc. of Oakland, N.J. developed and manufacture a centerless grinder assembly which has photoelectric sensors detecting the position of the trailing end of the workpiece during machining operations. The detected signal is processed and causes the regulating wheel to change its position with respect to the work wheel so that the configuration of the workpiece is modified. As the trailing end of the workpiece is detected by additional sensors, further signals are generated and processed which may cause the regulating wheel to again change its position with respect to the work wheel. Accordingly, the machined workpiece may include one or more tapered sections. The tapered sections may be gradual, or abrupt, depending upon the desired configuration of the workpiece. Royal Master's aforementioned prior art centerless grinder is widely used in commercial practice and is further described in its -106 patent.
The gauging system of the present invention may be used in conjunction with centerless grinder assemblies. It overcomes the shortcomings of the prior art by providing a system where the profile of a machined workpiece can be accurately determined by effecting relative longitudinal movement between a gauging device and the elongate machined workpiece.
Although the present invention is particularly effective when used in conjunction with centerless grinder assemblies, it may also be used to determine the dimensions or profile of various types of elongate workpieces such as wires, rods, pins, shafts, etc. as well as optical fibers and the like.